Examination of Flawed Superconducting Thin Films

Abstract

Mutual inductance measurements of a two-coil apparatus are used to study 200Ålead and indium films with manually placed flaws. We found that a scratch of approximately 40μm across the diameter of our films increases the mutual inductance of the coils by a factor of 100. A bulk lead film (1300Å) with a 2mm hole in the center was placed on top of different portions indium films and we found that if the portion of the exposed indium film was not damaged then regardless of the quality of the non-exposed portions the results below Tc,In were indistinguishable from that of a flawless indium film with no lead “shield”.